An Air Force F-16 flies away after refueling midflight from a KC-135 Stratotanker during a Red Flag exercise in February. (AP)

NELLIS AIR FORCE BASE, NEV. — After more than a dozen years fighting wars against unsophisticated opponents and technology in Iraq and Afghanistan, the Air Force is refocusing its training on tests ripped from the headlines — surface-to-air missiles, chemical weapons and cyber warfare.

The training, according to military analysts and the service's top boss, a former fighter pilot himself, is vital to the service as it faces increasingly sophisticated threats from Eastern Europe to the Pacific. It comes as the Pentagon tries to shift its focus from counterinsurgency struggles to bigger, more deadly fights.

"One of the things that has changed over the last five to 10 years actually is that we haven't done as much of this because of the commitment to Afghanistan and Iraq," said Gen. Mark Welsh, Air Force Chief of Staff. "Just because of time, resources."

The Air Force offered USA Today exclusive access to commanders, pilots and briefings at the round-the-clock Red Flag air combat exercise just north of the Las Vegas strip.

The exercise started in 1975 from hard lessons learned in Vietnam. Most pilots were shot down there in their first 10 missions. The idea here is to replicate the complexity and chaos of the fight, allowing pilots to get their combat baptism without getting fired at with real bullets and missiles.

"Which means you have to make Red Flag feel like a combat environment," Welsh says.

The chaos and complexity of Red Flag is essential training for pilots, says Richard Aboulafia, an analyst of military aircraft at the Teal Group, a consultancy. The Pentagon's preoccupation with counterinsurgencies over the last decade has sapped resources from training against potential enemies with sophisticated air defense systems, he says.

"Afghanistan and Iraq involved a huge budget surge, but all of it went to personnel, logistics and systems that have no application in a conflict with a peer adversary," Aboulafia says. "Ships, aircraft, surveillance systems and other tools that a superpower needs were given a very low priority. In short, we skipped a defense budget cycle in order to pay for a giant nation-building and counterinsurgency exercise."

Important training such as Red Flag may been starved for resources, says Michael O'Hanlon, a military analyst at the Brookings Institution. But that may have been because it has spent too much money on the F-35 fighter whose $400 billion price tag makes it the most expensive weapon ever.

"The USAF has had lots of money this decade so if it's not in good shape, it's largely the service's fault," he said.

The (simulated) fight

For this round, under a dazzling blue sky and 110-degree Nevada heat, 116 jets, planes and helicopters roar and clatter at all hours. Airmen, mostly American with a sprinkling of allies this time from Singapore and France, face a different scenario each weekday. Air Force units, a year in advance, request the type of training they need most, and it generally reflects threats you read about every day, though the Air Force insists they are not targeting specific countries.

The week's schedule shows the various challenges: One day they tackled establishing a no-fly zone by winning the sky against an enemy with surface-to-air missiles and jets – think Libya 2011. On Tuesday they were fighting through sophisticated air defenses to destroy chemical weapons sites, while on Wednesday they tried to overcome surface-to-air missiles (again), finding and destroying mobile missile launchers on sight without the benefit of confirmation from headquarters. On Thursday, they went on a manhunt for a high-value target, and on Friday they were rescuing an airman downed far behind enemy lines.

A common thread is the threat of surface-to-air missiles, the weapon that destroyed Malaysian Airlines Flight 17 last week, killing nearly 300 people.

Those anti-aircraft missiles have grown in sophistication in the last 15 years as their guidance systems have been digitized, says Col. Jeff Weed, commander of the 414th Combat Training Squadron.

War gamers increase the difficulty of the exercises as the week progresses and pilots improve, Weed says. They also face pilots, like Weed, in opposing jets, attempting to thwart their plans.

Budget cuts last year prompted the Air Force to cancel one of four Red Flag sessions and reduce flying time across the service. The result was rust, Weed says. Pilots couldn't graduate to the most difficult training runs and losses, though not real, were too high.

Training funds have been restored in part, and the results have been dramatic, he says. Losses are at least 50% lower.

"Our Air Force is getting back to train the way we need it to," Weed says.

Red Flag rookie, and grizzled veteran

Lt. Brenden Torphy, 25, says the intensity of the training — new airfield, radio signals, attention to safety with so many planes in the sky — was overwhelming at times. But he's steadily improving, he says, although it's hard to top what he's already done.

The Philadelphia native received flying lessons for his 14th birthday, went to ROTC at Penn State University and had attained a commercial flying license by graduation. Today, he's flying the most sophisticated fighter in the world, the F-22.

This is as close as he's come to combat.

The training here has taught him to be more thrifty with fuel to stay in the fight longer, he says. Continual briefings on surface-to-air missiles and last week's catastrophe in eastern Ukraine have had an effect, too.

"It's kind of in our collective consciousness now," Torphy says.

For Lt. Col. Raymond Millero, 42, says this week's Red Flag allows him to return as a commander of the 79th Fighter Squadron and sharpen his skills for a more intense fight than his recent deployment to Afghanistan.

"We don't want to show up to a major, intensive war without practice," he says.